John O'Brien

Everybody seems to know who the father of Rachel's baby is except the man himself. Meanwhile, Phoebe and Joey lie about a gas leak to get into Monica and Chandler's apartment.

Cristina treats a former Seattle Grace scrub nurse and is forever changed. Izzie's past comes back to haunt her and makes a case difficult.

Bailey interferes in Meredith and Derek's relationship. Alex works hard to gain the trust of a shy patient with a gargantuan tumour.

Meredith fights to keep her emotions in check when a secret about her mother is revealed; Alex and Izzie grow close.

Meredith and Cristina lie to each other about their relationships; George is given an unpleasant task; Alex learns the results of his exam resits.

Jonah is assigned to work in the gun section and refuses to sell to anyone he deems suspicious. Glenn tries to buy the store's entire stock of morning-after pills.